First results from SMAUG: Insights into star formation conditions from spatially-resolved ISM properties in TNG50. (arXiv:2006.16314v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Motwani_B/0/1/0/all/0/1">Bhawna Motwani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Genel_S/0/1/0/all/0/1">Shy Genel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bryan_G/0/1/0/all/0/1">Greg L. Bryan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_C/0/1/0/all/0/1">Chang-Goo Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pandya_V/0/1/0/all/0/1">Viraj Pandya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Somerville_R/0/1/0/all/0/1">Rachel S. Somerville</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_M/0/1/0/all/0/1">Matthew C. Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ostriker_E/0/1/0/all/0/1">Eve C. Ostriker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nelson_D/0/1/0/all/0/1">Dylan Nelson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pillepich_A/0/1/0/all/0/1">Annalisa Pillepich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Forbes_J/0/1/0/all/0/1">John C. Forbes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pakmor_R/0/1/0/all/0/1">Rüdiger Pakmor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernquist_L/0/1/0/all/0/1">Lars Hernquist</a>
Physical properties of the interstellar medium (ISM) at sub-galactic
($sim$kpc) scales play an indispensable role in controlling the ability of gas
to form stars. As part of the SMAUG (Simulating Multiscale Astrophysics to
Understand Galaxies) project, in this paper, we use the TNG50 cosmological
simulation of the IllustrisTNG project to explore the physical parameter space
comprised of 8 resolved ISM properties in star-forming regions across a wide
range of host galaxy mass (M$_star = 10^{7-11}$ M$_odot$) and redshift ($0
leq z leq 3$). We deconstruct our simulated galaxies into regions of 1 kpc in
size, and measure the gas/stellar surface densities, gas metallicity, vertical
stellar velocity dispersion, epicyclic frequency and dark-matter volumetric
density representative of each region, and study them in the context of their
star formation activity and galactic environment (radial galactocentric
location). By examining the star formation rate weighted distributions of these
properties, we show that stars primarily form in two distinct regimes, which
are brought about by an underlying bi-component radial star formation rate
profile in galaxies. We examine how the relative prominence of these two
regimes depends on host galaxy mass and cosmic time, and compare our findings
with observations from the MaNGA IFU survey. Further, using principal component
analysis, we characterise the aforementioned parameter space to reveal a
high-degree of multicollinearity in relationships between ISM properties that
drive the distribution of star formation at kiloparsec scales. Based on this,
we find that a reduced three dimensional representation underpinned in essence
by a multi-variate radius relationship is sufficient to capture most of the
variance in the original 8D space.
Physical properties of the interstellar medium (ISM) at sub-galactic
($sim$kpc) scales play an indispensable role in controlling the ability of gas
to form stars. As part of the SMAUG (Simulating Multiscale Astrophysics to
Understand Galaxies) project, in this paper, we use the TNG50 cosmological
simulation of the IllustrisTNG project to explore the physical parameter space
comprised of 8 resolved ISM properties in star-forming regions across a wide
range of host galaxy mass (M$_star = 10^{7-11}$ M$_odot$) and redshift ($0
leq z leq 3$). We deconstruct our simulated galaxies into regions of 1 kpc in
size, and measure the gas/stellar surface densities, gas metallicity, vertical
stellar velocity dispersion, epicyclic frequency and dark-matter volumetric
density representative of each region, and study them in the context of their
star formation activity and galactic environment (radial galactocentric
location). By examining the star formation rate weighted distributions of these
properties, we show that stars primarily form in two distinct regimes, which
are brought about by an underlying bi-component radial star formation rate
profile in galaxies. We examine how the relative prominence of these two
regimes depends on host galaxy mass and cosmic time, and compare our findings
with observations from the MaNGA IFU survey. Further, using principal component
analysis, we characterise the aforementioned parameter space to reveal a
high-degree of multicollinearity in relationships between ISM properties that
drive the distribution of star formation at kiloparsec scales. Based on this,
we find that a reduced three dimensional representation underpinned in essence
by a multi-variate radius relationship is sufficient to capture most of the
variance in the original 8D space.
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